Wheelchair safety device

Abstract

A wheelchair safety device comprises a brake lever, four link levers, an upper brake plate, a brake wheel, a lower brake plate, a parking wheel, and an angularly adjustable mounting plate. One end of the first, the second and the third link levers is respectively articulated at the brake lever, another end of the first and the second link levers are articulated with one end of the fourth link lever. Another end of the fourth link lever is articulated at the upper brake plate and another end of the third link lever is articulated at the lower brake plate. One end of the upper and the lower brake plates is respectively articulated at the angularly adjustable mounting plate, and another end thereof is mounted with the brake wheel and the parking wheel, respectively. The brake wheel and the parking wheel respectively act on the wheelchair.

1. A wheelchair safety device comprising: a brake lever, a first link lever, a second link lever, a third link lever, a fourth link lever, an upper brake plate, a brake wheel, a lower brake plate, a parking wheel, and an angularly adjustable mounting plate; wherein one end of the first link lever, the second link lever, and the third link lever are respectively articulated at the brake lever, and another end of the first link lever and the second link lever are articulated with one end of the fourth link lever, while another end of the fourth link lever is articulated at the upper brake plate and another end of the third link lever is articulated at the lower brake plate; one end of the upper brake plate is articulated at the angularly adjustable mounting plate, and another end of the upper brake plate is provided with an axle on which the brake wheel is mounted, while one end of the lower brake plate is articulated at the angularly adjustable mounting plate, and another end of the lower brake plate is provided with an axle on which the parking wheel is mounted via an one-way bearing; wherein the fourth link lever drives the upper brake plate so as to make it pivot on an articulation point of the upper brake plate and the angularly adjustable mounting plate, while the third link lever drives the lower brake plate to make it pivot on an articulation point of the lower brake plate and the angularly adjustable mounting plate; wherein the brake wheel and the parking wheel respectively act on wheelchair tires. 
     
     
       2. The wheelchair safety device of  claim 1 , wherein a line joining an articulation point of the upper brake plate and the fourth link lever, the articulation point of the upper brake plate and the angularly adjustable mounting plate, and an articulation point of the upper brake plate and the brake wheel forms a triangle; while a line joining an articulation point of the lower brake plate and the third link lever, the articulation point of the lower brake plate and the angularly adjustable mounting plate, and an articulation point of the lower brake plate and the parking wheel also forms a triangle. 
     
     
       3. The wheelchair safety device of  claim 1 , wherein longitudinal grooves or mesh-like grooves are evenly distributed on surfaces of the brake wheel and the parking wheel. 
     
     
       4. The wheelchair safety device of  claim 1 , wherein the angularly adjustable mounting plate is a porous mounting plate on which holes are evenly distributed. 
     
     
       5. The wheelchair safety device of  claim 1 , wherein the angularly adjustable mounting plate is a mounting plate of the type on which curved through slots are arranged. 
     
     
       6. The wheelchair safety device of  claim 1 , wherein the one-way bearing comprises a ratchet. 
     
     
       7. The wheelchair safety device of  claim 1 , wherein the brake wheel is an eccentric wheel. 
     
     
       8. The wheelchair safety device of  claim 1 , wherein the brake lever connects with a handle at its end portion. 
     
     
       9. The wheelchair safety device of  claim 1 , wherein the angularly adjustable mounting plate is adapted for use with wheelchair tires of various dimensions.